How to blend dual-b...
 
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How to blend dual-band?


(@devonshire)
White Dwarf Customer
Joined: 4 years ago
Posts: 23
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Hi!

Still getting used to APP 1.082, and trying to follow this tutorial, but I'm getting stuck...:

https://www.astropixelprocessor.com/community/main-forum/having-trouble-eith-colors/#post-2788

The target is the Western Veil.
For better or worse, I have some 600s lights, shot with a CLS-CCD filter, and some 90s lights, just shot with a UV-IR. The camera is a Nikon D5300.

I'm trying to load the CLS-CCD ones using the 0) "Ha-OII" algorithm. I would expect that when loading the lights, I'd have a similar joint channel option after selecting files, but no. It's one or the other, so I pick one (say, Ha...) and load that into session #1. Then I went back to load the same lights a second time, thie time for assignment to OIII and session #2.

But... that does not work, because the same physical files will only assign to one channel, and the Ha's I've already loaded just switch over to OIII.

Undaunted by that, I decided to try to load flats. These also wanted to be loaded to a specific channel, and behaved similarly to the lights.

Clearly, loading the same file more than once. for different purposes, is a no-no. 🙂

So... Given that I'd like to emphasize Ha and OIII from my various lights, how should I be loading my lights and flats?

Thanks!

- Bob


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(@devonshire)
White Dwarf Customer
Joined: 4 years ago
Posts: 23
Topic starter  

Just to expand on this...  (see attached screen shots)

It looks like the "Ha-OIII color" choice is intended for just such a case as loading images from a DSLR with a CLS-CCD (dual-range) filter.  

BUT...the next step asks me to pick a channel. Seems redundant given the prior pick, but in any case, I don't see any option that corresponds to the prior Ha-OIII choice - it's either single-channel or RGB.

So (despite the 1-channel disclaimer at the top of the box), I did try to load the lights, once for Ha and Session #1, and a second time for OIII and session #2. No joy, the already-loaded files just flipped from Ha+Sess1, to OII+Sess2.

So...the "Ha-OIII color" choice, as described, looks like it intended for exactly what I wanted to use it for, but I don't seem to be able to use it.

Is this a bug, or should I be doing something different?

Thanks for your help with this...

Screenshot 20200722 104433
Screenshot 20200722 104755

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(@pogo)
Hydrogen Atom Customer
Joined: 5 years ago
Posts: 1
 

I have the same question. Not sure what to do there


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4736
 

Ok, so to make this a bit clearer for me; what happens if you just load in the images with the filter, using the "extract Ha" algorithm? And same for OIII? Does that work?

I think what you want is to load in the RGB images and select the "split channels" option to make them R, G and B files. Then use the lights with the filter and do the above, after which you can load them all in again and choose the correct channel for each (R, G, B, Ha, OIII). Those integrations can then be combined in the "combine RGB" tool.

The Ha-OIII algorithm is just to get a RGB image straight from those filters, but not necessarily handy for combining with regular RGB.


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(@devonshire)
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Joined: 4 years ago
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Topic starter  

Thanks, Vincent!

You're saying to split everything into individual channels?  R+G+B+Ha+OIII, and the combine ?

I can try that - but if that's the route, what is the tooltip for "Ha-OIII color" talking about?   Looks like an interesting option, but it's not at all clear how one could actually load files with it...


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4736
 

It will do the same as the Extract Ha and Extract OIII, but makes a color integration automatically for you. This is better than just the regular demosaic algorithm and will produce a less noisy integration.


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(@devonshire)
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Joined: 4 years ago
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Topic starter  

Thanks!

 

So... just to unconfuse me... 🙂

If I was using the  "Ha-OIII color" pick, rather that the all-channel split above, then when panel 2 comes up to load the lights, the correct pick would be RGB and not any of Ha/OIII/etc...?

Supplemental question, once the above is out of the way...  I assume that correct flat handling for either of the above (all-channel split or Ha-OII color), would be to load the flats with the same settings as the lights.  Correct? 

 


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(@vincent-mod)
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Joined: 5 years ago
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First part: that's just to label the data really and has no real data effect. but you could select RGB there as that's what is created indeed.

So for flats you want to use the RGB flats for the RGB lights, these will first be calibrated and then split. For Ha and OIII you need the flats for that filter. It's probably less confusing when processing first the RGB and then the Ha-OIII data anyway.


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(@devonshire)
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Joined: 4 years ago
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Topic starter  

<<First part: that's just to label the data really and has no real data effect. but you could select RGB there as that's what is created indeed.>>

Ahh !!!   Thus endeth the mystery 🙂

Re: Flats - that's fine - makes sense.  

Thanks, Vincent - I'm off to try things now.

 

 


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(@vincent-mod)
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Great! Please let us know how it went. 🙂


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(@devonshire)
White Dwarf Customer
Joined: 4 years ago
Posts: 23
Topic starter  

Well...

Trying to go down the road of Ha-OIII + RGB -> 'combine RGB' road just led to frustration.   There are no tooltips to explain the 'combine RGB'  module features, and the module does not appear to be aimed at this use case, anyway.  

Stepping back to try splitting out the individual channels and will take another run at 'combine' after that...

 


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(@supercreative)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 5
 

 

I choose the extract Ha option in the 0. tab and run that all the way to integration and save it as .fit and call it Ha, then I go back to the 0. tab and select extract 0III, it will tell me I have to renormalize, tab 5. so I do, then integrate and save as a .fit called OIII. Then I go to the 9. tab and select combine RGB and import the Ha once and the OII twice. I set the Ha to red, the OII to green and the second OII to blue. Works well. Learned it from here:

I've also attached the combine RGB settings from the tutorial that are a good starting point.

Screen Shot 2020 07 15 at 3.04.32 PM
Screen Shot 2020 07 15 at 3.17.28 PM

 


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(@devonshire)
White Dwarf Customer
Joined: 4 years ago
Posts: 23
Topic starter  

Thanks!   I'll run through the video a couple of times, and then see how I do.  


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4736
 

Yes, that’s a good flow indeed when only using narrowband Ha and OIII.


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